Browsing by Subject "Physics"
Now showing items 21-40 of 49
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Measurements Of Radon Permeability Through Some Membranes
( Qatar University , 1994 , Article)The diffusion of 222Rn through different types of membranes has been studied by an equilibrium method using a Si surface barrier a-detector with a resolution of 14 keV FWHM for ^'Am. The permeability constant for Aluminized ... -
Microwave Spectra of 13CH3C15N and 13CH3 13C 15N Molecules In the Frequency Range 17-95 GHz
( Qatar University , 2002 , Article)Some microwave frequencies of the v^ + Vg vibrational combination band for the two isotopes CH^C N and CH^ C N of methyl cyanide were measured in the frequency range 17-95 GHz, for the transitions AJ = 1<-0, AJ = 2<-1, AJ ... -
Mossbauer Effect Study of Libyan Desert Silica Glass
( Qatar University , 1981 , Article)The Mossbauer effect and X-ray fluorescence techniques are applied to study the Libyan Desert Silica Glass. The X-ray flourescence proved the existence of 13 elements in each sample of five glass types with differences in ... -
Mossbauer Effect Study of the Cations Distribution and its Influence on the Electric Field Gradient of the Cdx Co1-x Ferrite System
( Qatar University , 1982 , Article)In the ferrite system Cd,Co,_x Fe; 04 (X=0.0, O.I, 0.2, ....... , 1.0). it was found that the introduction of Co2'1' decrease the EFG at the octahedral B-site. This was attributed to the distributions of the different ... -
Mossbauer Effect Study of the Hyper fine Structure of the Different Phases of Iron in the Portland Cement Produced in Qatar
( Qatar University , 1981 , Article)Various samples of the raw materials used in the manufacture of Portland cement in Qatar, the clinker produced and the cement itself were studied by using Mossbauer Effect and X-ray diffraction analysis in order to investigate ... -
Mössbauer effect study of Li21+Me4+Fe63+O122−spinels
( Baltzer Science Publishers, Baarn/Kluwer Academic Publishers , 1986 , Article)Mossbauer effect spectra are obtained for the cubic ferrites Li2 Me Fe6 O12 (where Me4+ is one of the tetravalent elements Ge, Si and Ti) at 78K up to their magnetic transition temperatures. In a rather large temperature ... -
Mössbauer study of ZnxNi5/3−xFe1Sb1/3O4 spinel ferrite
( Springer Verlag , 1985 , Article)The antimony substituted nickel ferrite ZnxNi5/3–xFe1Sb1/3O4 with different values ofx are prepared, checked by x-ray and studied with57Fe Mössbauer spectroscopy over a wide temperature range. Characteristic spectra of ... -
Multielement Analysis Of Suspended Particulates In Doha (Qatar) Air Before And During The Gulf War
( Qatar University , 1994 , Article)Efforts have been made to study the effect on Qatar atmosphere from the burning of Kuwait oil fields during the Gulf war. Analysis of suspended air particulates was done by X-ray fluorescence technique. Eight elements were ... -
Neutron Diffraction and Mossbauer Effect Study of a Cobalt Substituted Zinc Ferrite
( Qatar University , 1982 , Article)The mixed cubic ferrite Zno.g5 €00.15 Fez 04 is studied by neutron diffraction and Mossbauer effect techniques at the temperature range 4.2 - 293 °K. The obtained spectra by both methods at low temperature show a long range ... -
Neutron Diffraction And Mossbauer Effect Study On A Mixed Rare Earth Garnet
( Qatar University , 1983 , Article)A powder sample of Y^YbFesO,; was prepared using the ceramic technique. X-ray diffraction pattern showed a single phase of the garnet type structure with a lattice constant 12.323 A". Specific heat for this composition was ... -
Numerical investigation of dusty tri-hybrid Ellis rotating nanofluid flow and thermal transportation over a stretchable Riga plate
( Nature Research , 2023 , Article)Due to high-ultra thermic significances, the nanosize materials are used in various chemical and mechanical engineering, modern technology and thermic engineering eras. For industrial growth of a country, one of the biggest ... -
ON THE CRYSTAL AND HYPERFINE PARAMETERS OF THE HEXAGONAL Ba Cax Sr1_xFe4 O8 MONOFERRITES
( Qatar University , 1983 , Article)The alkaline earth monoferrites BaCaxSr1-xFe4O8 with X = 0,0.5and 1, were studied by Mossbauer spectroscopy and neutron diffractometry over a wide range of temperatures (78 - 900 K). The lattice constants were obtained ... -
On The Existence And Uniqueness Of Solutions Of A Functional Differential Equation
( Qatar University , 1983 , Article) -
On the origins of antiferromagnetic order in a frustrated spin system at high pressure
( National Academy of Sciences , 2015 , Article)In this letter, I would like to complement the discussion on the antiferromagnetic (AFM) order in the model-frustrated quantum magnet SrCu2(BO3)2 at high pressure. -
On Using the One-Exposure Method for Stress Measurements by X-Rays in Technology and Scientific Research
( Qatar University , 1982 , Article)The paper discusses the connection between macroscopic internal stresses and the technological character of technical materials. The basic theoretical relations which are used with X-Ray tensiometry of macroscopic internal ... -
The Optical and Electrical Properties of Low Density Polyethylene Films in CuSo4 Solution
( Qatar University , 2005 , Article)The optical and electrical properties of pure and treated low density polyethylene (LDpE) were investigated. These measurements have been carried out at various times of immersion for LDPE films in 10% solution of CuSO+. ... -
The Optical properties of Cadmium Stannate (Cd2SnO4) Thin Films Prepared by Chemical Spry Pyrolysis Technique
( Qatar University , 2004 , Article)Thin films of cadmium stannate were prepared using thermal chemical spray pyrols: Cadmium stannate' solution (0.2M) was prepared by dissolution of CdCl25H2O in C2H5OH tion of SnCl23H2O in CH3COOH at molar 2:1, respectively. ... -
Optical Properties Of Oxidated Blown Asphalt Films
( Qatar University , 1996 , Article)Films of purified blown asphalt of high grades of oil and the accompanied adulterated particles derived from its manufacturing process, that is, it was purified 98%. This study focused on optical properties in the wavelength ... -
p-cds/n-Si Anisotype Heterojunction solar cells wih Efficiency of 6.4%
( Qatar University , 2005 , Article)In the present paper, p-CdS/n-Si heterojunction solar cells are prepared for the first time by the spray pyrolysis technique. Using such low-cost method, cells with 6.4'/o AM1 conversion efficiency ina O.ZZ fill factor ... -
Strain Broadening of E.P.R. Linewidths in Fe/Mgo Single Crystals and Powders
( Qatar University , 2004 , Article)The E.P.R. linewidth of the M= + 1/2 <-» -1/2 transition of Fe3+ spectrum of Fe/MgO single crystals and powders have been measured at 9 GHz before and after annealing. The nominal iron concentrations ranged from 310 to ...